Muammar Gaddafi's former intelligence chief, who is wanted by France, the international criminal court and Libya, has been charged by Mauritania's public prosecutor in a secret court hearing, his first public appearance since fleeing Libya's crumbling regime to the desert country.

Abdullah Senussi, a confidante and brother-in-law to Gaddafi, will face trial for entering Mauritania illegally with a falsified Malian passport, a crime that carries a maximum three-year jail term, a judicial source said.

Senussi, who had been held in a villa in the Mauritanian capital of Nouakchott since March, is alleged to be behind a massacre in Tripoli's notorious Abu Salim prison, which left around 1,200 inmates dead, and triggered Libya's revolt when lawyers sought to reopen the case last year.

A Mauritanian security official said an entourage of elite presidential guards had whisked Senussi overnight into the multi-domed courthouse. "He looked well, and seemed in good spirits under the circumstances," the official said.

"Normally he would now be held in the main prison, but our understanding is he is staying in a special location guarded by troops," the official said.

A judicial source said a trial was unlikely to begin soon. "A [trial start] date doesn't have to be set for up to three years, so that will buy the authorities time," he said.

France wants to try Senussi in connection with the 1989 bombing of an airliner over Niger in which 170 died. An ICC warrant is seeking Senussi for crimes against humanity in Libya.

British officials have also indicated they could seek access to him in relation to the Lockerbie bombing, in which Senussi is suspected of playing of a role.

Diplomats said there had been no clear indication what Mauritanian authorities planned to do with the high-profile prisoner. "More than anything else, the Senussi issue has been about smoke and mirrors," a diplomat said.